| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device for a wheel which improves durability by securing an appropriate preload during straight running and appropriate bearing rigidity during turning and which achieves cost reduction by flexibly responding to each bearing specification. SOLUTION: A diameter of pitch circle of double row ball groups is set larger at the outer side than the inner side. An inner rolling face 6a of an inner ring 6 is structured with a radius r of curvature, which is formed over a range from the vicinity of a contact point P contacting the balls 4 at an initial contact angle α to a groove bottom and a radius r1 of curvature, which is smaller than the radius r of curvature and formed over a range from an inflection point P1 contacting the balls 4 at the contact angle α1 to a large outer diameter 6b of the inner ring 6. The radii r, r1 of curvature are set to the ranges of 1.05d<2r≤1.10d and 1.01d≤2r1≤1.05d with respect to the diameter d of the balls. When the inflection point P1 of the two radii r, r1 of curvature is determined as α1=α+Δα under α=30 to 45°, Δα is set to the range of 2 to 8°. COPYRIGHT: (C)2010,JPO&INPIT
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